The conventional combine cutters utilize a plurality of reciprocating knife blades in conjunction with three-inch center guards. This type of cutter causes the plants to be bent forwardly and slidewardly and crowds or bunches the plants as the knife moves relative to the guards. The sideward movement of the stems of the plants causes the plants to be inclined in alternate directions from left to right as they fall rearwardly onto the platform of the header. This arrangement can cause bunching and uneven feeding by the feed augers of the header. The use of 3-inch knives with 3-inch center guards causes a considerable amount of material to be gathered and bunched between adjacent guards for cutting. This large amount of material is initially compressed before it is severed by the moving blade in conjunction with the wear plate cutting edge on the guard. This requires considerable power to be applied to the sickle bar to cut the plants and causes further random orientation of the cut plants as they move rearwardly onto the platform.
Endless chains carrying a plurality of cutting knives that move relative to guards were first introduced by Sweet in 1874 in U.S. Pat. No. 157,243. Additional endless chain cutting mechanisms for mowing machines and harvesters are shown in the following patents:
U.s. pat. No. 259,757 -- Guptill -- June 20, 1882 PA1 U.s. pat. No. 369,096 -- Brown -- Aug. 30, 1887 PA1 U.s. pat. No. 437,943 -- Spratt -- Oct. 7, 1890 PA1 U.s. pat. No. 682,875 -- Love -- Sept. 17, 1901 PA1 U.s. pat. No. 970,019 -- Grosthwait -- Sept. 13, 1910 PA1 U.s. pat. No. 1,000,949 -- Rosean -- Aug. 15, 1911 PA1 U.s. pat. No. 1,053,289 -- Jacobs et al -- Feb. 18, 1913 PA1 U.s. pat. No. 1,057,392 -- Helgeson -- Mar. 25, 1913 PA1 U.s. pat. No. 1,851,840 -- Huff -- Aug. 29, 1930 PA1 U.s. pat. No. 2,714,280 -- Baker -- Oct. 12, 1954 PA1 U.s. pat. No. 2,821,060 -- Schoffner -- Nov. 24, 1954 PA1 U.s. pat. No. 2,941,345 -- Schaeffer -- June 7, 1957 PA1 U.s. pat. No. 2,948,099 -- Johnson -- Nov. 21, 1958 PA1 U.s. pat. No. 3,029,584 -- Johnson -- Apr. 20, 1960 PA1 U.s. pat. No. 3,561,202 -- Tupper -- Feb. 9, 1971 PA1 U.s. pat. No. 3,681,901 -- Buchele et al -- Aug. 8, 1972